Plug-in electric vehicles (PEVs) have become a key factor driving towards smart cities, which allow for higher energy efficiency and lower environmental impact across urban sectors. Industry vision for future PEV includes the ability to recharge a vehicle at a speed comparable to traditional gas refuelling, i.e. <3 min. per vehicle. Such a technology, referred to as ultra-fast charging (UFC), has drawn much interest from research and industry. However, UFC poses unprecedented challenges to existing electricity supply infrastructure due to its large power density, impulsive, and stochastic load characteristics. Planning the locations and electric capacities of UFC stations is critical to preventing detrimental impacts. In particular, efforts must be made of mitigate grid asset depreciation, grid instabilities, and deteriorated power quality. The authors first review planning methods for conventional charging stations. Next, they discuss outlooks for UFC planning solutions by drawing an analogy with renewable energy (RE) source planning. This analogy is based on the similar power density and stochastic characteristics of RE and UFC. While this study mainly focuses on UFC planning from the power grid perspective, other urban aspects, including traffic flow and end-user behaviour, are examined for feasible UFC integration within smart cities.

Technology selection and sizing are key aspects of the design procedure for energy storage systems (ESSs) for power system applications. Here, the authors extended existing methodologies for optimal sizing and technology selection by introducing self-discharge effects, and variable ESS lifetime as a function of energy throughput, which results in a non-convex optimisation problem. Simulation results confirmed that making operational lifetime a variable has a significant impact on the results of the optimal sizing and technology selection problem. More specifically, considering the variable ESS lifetime as a function of energy throughput showed that ESSs of various technologies tend to operate such that their operational lifetimes would far exceed their calendar lifetimes. This has confirmed the importance of considering operational lifetime as a variable rather than a fixed value, as without doing this could result to underutilised and/or oversized systems. Taking into account, the self-discharge effect showed that the electrochemical technologies considered here, with the exception of supercapacitors, have low levels of self-discharge, which are largely obscured by the significant impact of the roundtrip efficiency characteristic.

Regulatory, commercial and governance arrangements form an integral part of any power system. They ensure that the underlying physical system fulfils the critical public function of electricity supply within agreed social and environmental constraints. If either the physical system or societal expectations change, the regulatory, commercial and institutional framework will need to adapt in response. This is necessary to ensure continued good outcomes for consumers at a reasonable cost. Power systems in many countries are going through rapid and substantial change, as a result of the twin pressures of decarbonisation and technological innovation. The power system is moving from one dominated by large-scale, transmission-connected, flexible thermal power stations serving passive demand, to an integrated smart system connecting increasingly distributed and intermittent energy resources integrated with an active demand side. As a result, there is a need for far-reaching reforms of institutions, charging arrangements, market structures and regulations. Fundamental notions, such as security of supply and the universal service obligation need to be revisited. This is a challenge for policy makers and regulators wherever these changes are taking place.

Maintaining a high overall network reliability remains one of the most critical requirements for advanced metering infrastructures (AMIs) in smart grid. Ensuring reliable networks not only determines the robust communications of an AMI, but also guarantees assured information delivery in the access network. To prevent any communication failures, incremental designs based on legacy networks should be carried out in advance to improve the overall redundancy. Current communication architecture of an AMI follows a traditional access network structure with a tree-based topology, which does not always satisfy high robustness and is prone to network failures. To address the challenge, this study conducts a reliability study of the access network in an AMI. Specifically, this study first examines the basic network topology adopted in an AMI access network and its underlying connectivity issues. Secondly, this study proposes two practical solutions as parts of incremental network design to improve the communication robustness of existing communication architectures. Thirdly, mathematical models are formulated to solve network connectivity problems, for maintaining a high overall network reliability, while minimising the communication deployment cost at the same time. Simulation results are provided from the aspects of minimal path sets and minimal cut sets to demonstrate the redundancy analysis.